The present invention relates generally to digital communication systems. More specifically, the invention relates to a system and method of synchronizing a plurality of base stations in a cellular communication network.
The proposed 3rd generation (3G) wireless protocols require an approach that is based on a simple, but costly procedure of requiring each base station to be externally synchronized to a highly accurate external source. One technique which supports base station synchronization requires that a base station passively listen to synchronization transmissions from its neighbors on a channel, such as a synchronization channel (SCH) or a common control physical channel (CCPCH), and follow procedures similar to those performed by user equipment (UE) in order to synchronize. Another approach requires each base station to occasionally send a special synchronization burst in coordination with one or more of its neighbors listening for the transmission. Yet another approach has UEs measure the time difference of arrival (TDOA) of transmissions from each of two cells. These techniques utilize a precisely accurate source in every base station. Since each base station has this source, these techniques are costly and inconvenient.
Therefore, there exists a need for a system and method that allows fast, efficient, and less expensive synchronization between operational base stations without consuming additional physical resources.
There also exists a need for a system which provides accurate synchronization using a minimum number of interruptions of normal service, as well as reduced message traffic between the Node B and the radio network controller (RNC).